Whilst waiting on brake parts to arrive - thought I might renew the spark plugs.
has anyone tried doing the front two plugs with the a/c compressor in place? Looks like it might just be possible with this unit... thoughts from those who have tried it?

 

Yes, the compressor can stay in place. I can't recall if I needed to use the special spark plug wrench in the tool kit with the swivel joint or not.

 

What bits n pieces did you take off to get at the plugs?

 

I don't think I took off anything aside from the engine cover, which you already have off. It's been a while since I did it though.

 

I did the job a few times and it got easier after the third time.
So I'll save you some trouble.
Get a deep spark plug socket with a hex on the back end.
Make sure it will fit in the gap available.
Use a ratcheting box wrench like GearWrench,
I never found a combination of socket/ratchet that I could get in the space.
Also make sure that the ratcheting box wrench has a very, very small functional angle.
The first time took me about 10 hours.
Eventually got it down to three.

 

Spark plug set due any day now.. ordered up the spec as per in the handbook, NGK BR7EF . Didn't like to chance removing any of the existing plugs with the amount of oily dust and various detritus that had collected in the spark plug recesses, so I set about cleaning the area best I could. I find the WD40 degreaser product (not the penetrating oil) really great at shifting grease and baked on oil deposits . It's fast acting and has a vigorous pressure spray behind it. Used lots of absorbent rags and paper towels to soak up the dissolved muck. I found the best way to clear the actual spark plug recesses was to spray the degreaser into the recess, leave it for an hour or so to completely dissolve and loosen any debris and then using a length of stiff plastic tube on a compressor air pistol, blast the whole lot out while covering the recess with a rag. This appears to have completely cleaned each plug recess really well and I'm confident that nothing can now fall into the cylinders when the old plugs are removed. I ordered up a replacement distributor cap gasket for the Marrelli distributor after reading the debate in another thread on the merits and/or need for it. I figured that if it was there to start with, I guess there was a good reason for it so I will replace it. However, it has to be one of the highest price gaskets per square millimetre that ive bought in a while!

Marrelli distributor gasket

Cleaned out spark plug recess

 

I don’t use A/C in the race car but it seems to me that the simple way would be to remove the A/C using the flexibility of hoses to shift it out of the way.
If it took me More than 10 minutes to change plugs on the race car it’s because someone interrupted me. Blast Track debris off with air hose, spin out 12, spin in 12( gap checked previously) Plug wires back on. 1-6 A side white B 1-6 side red.

 

Okay, my AC compressor went on the scrap pile yesterday, and the cruise control bellows went in the pile of parts that might go back on "some day". Now the front six plugs are pretty easy to get to, but I pulled the throttle pedestal (as per Living With a Classic's video on the subject) to get to the rest. How did you make it a ten minute job? You running carburetors?

 

Race car, so yes. While there may be people around capable of getting the fuel injection modified enough to work on a race car I’m not one of them.
I carefully followed the megasquirt website and watched people spending years trying to get it working properly.
Group 44 used the stock intake manifold ( with a slight modification get 450 horsepower and beat the Corvettes at the Run Off’s. After the XKE they raced the XJS and went to Weber’s and made over 500 horsepower.
A properly modified Fuel injection system Makes even more power but The few people capable of doing that want a fortune for that knowledge.
I did prepare one XJS for Chump Car racing ($500 cars) that used fuel injection. We kludged a very early one that used the Bosch system and ran it as rich as we could( the early units had a way to richen or lean the whole system ) then we put a pair of Used Saab turbo’s ( little T2’s ) under each front fenders. With a FMU ( fuel management Unit ) (swap meet unit I bought for ( $45) that as boost went up tricked the ECM into adding more fuel.
Normally running that rich will foul the plugs but Champion was making gold palladium plugs that could tolerate the flood of fuel ( they don’t anymore)